Season the beef all over with 1/2 tsp. salt and a generous grinding of black pepper. Heat a large skillet over medium-high heat and add the olive oil. Sear the beef on all sides until well browned, about 5 min. total. Let cool, then refrigerate until cold, at least one hour, up to overnight (covered in plastic, and placed on paper towels to drain). I prefer a cast iron skillet for searing!

Meanwhile, make the filling. Place the spinach in a clean kitchen towel or paper towels and wring out as much liquid as possible. Melt the butter in a medium skillet over medium head. Add the spinach, artichokes, garlic, mushrooms and 1/4 tsp salt. Cook, stirring occasionally, until the mixture is dry and no liquid remains in the skillet, about 4 minutes. Transfer the mixture to the bowl of a food processor and let cook to room temperature.

Add the Boursin spread and Parmesan to the cooked mixture and process to a paste. Refrigerate the filling until you are ready to assemble the beef. (Can make the day before and refrigerate).

TO ASSEMBLE:

Remove the beef from the refrigerator. Lightly dust a work surface with flour and roll out 1 sheet of puff pastry. Cut in a 7 by 7 square. Repeat with our sheets of puff pastry until you get 6 – 7 by 7 squares. You might have to blend two cut pieces together. Beat together 1 egg and 2 T water.

Spread about one tablespoon of the spinach/mushroom mixture on top of each filet, pressing to flatten. Place one filet, mushroom side down, in the center of a puff pastry square. Using a pastry brush or your finger, paint the inside edges of the pastry with egg wash. Fold the pastry over the filet as thought wrapping a package and press the edges to seal. Place the packages seam-side down on the prepared baking sheet. Brush the egg wash over the tops and sides of each package, sprinkle with finishing salt if desired, and bake until the pastry is golden brown and an instant read thermometer registers 140 degrees F for medium rare, about 20 minutes. (You can prepare the packages and place in the refrigerator a few hours in advance, take them out and let come to room temperature 1 prior to baking)

About me:

I just completed my first family cookbook, called "Mary's Joy of Family Cooking". I decided to add the recipes to this blog. I will be adding new recipes along the way. I hope you enjoy it! Fondly, Mary